Can I use a variable throughout the entire script?

I am quite new to roblox scripting, I'm experienced with A similar language (Zero) in the past but don't know what to do here

This script is making a time variable for the entire scripts

time = 0  -- A time Variable for throughout the entire Workspace
while true do -- True boolean to repeat it all
    time = time + 1 -- add 1 to the time
    wait(1) -- wait .9 seconds in order to not overload the script
    if time == 820 then -- Makes sure the round can't go longer than 12 minutes
        time = 0 -- sets the time Variable back to 0
    end --ends the if statement
    print(time) --Prints "time" for debugging
end -- ends the While true

this is one of the many places I'm using that script

playerNames = game.Players:GetChildren() --Find the names of all the players
function kill() -- Kill all players
    for i = 1, #playerNames do --repeat until all the players are killed
        game.Workspace[playerNames[i].Name].Humanoid.Health = 0 --kill the player
    end ----finished
end -- Ends the kill() function

while true do
    if time >= 90 then --Time for people to choose character
        kill() -- Runs the kill() function

        if time >= 820 then
            for i=1, #playerNames do
                playerNames[i].TeamColor = BrickColor.new("White")
            end --Ends the "for" statement          
            kill() -- Runs the kill() function
        end --Ends this "if" statment
    end -- Ends the "if" statement
end